Mount Kasumizawa, Mountain summit in Matsumoto, Japan.

Mount Kasumizawa is a mountain in Nagano Prefecture and part of the Hida Mountain Range, rising to 2,646 meters (8,681 ft). The terrain features steep rocky slopes and narrow trails that demand skill and experience to navigate.

In summer 1902 Kojima Usui, a founder of the Japanese Alpine Club, climbed from Sawatari up the Kasumizawa valley and crossed the ridge into Kamikochi. Walter Weston reached the summit in 1913 via the Yauemonzawa route. The trail from Tokugo Pass was only opened in 1984; before that only variation routes such as Yauemonzawa existed.

The name comes from Kasumizawa, the valley on the Azusa River's southeast side whose headwaters rise on the mountain. The summit holds a second-order triangulation point, and the Tokugo Pass hut below keeps its Taisho-era old building as a museum, registered as a national tangible cultural property in 2011.

The main hiking route begins at Myojin and approaches through Tokugo Pass. Only experienced climbers should attempt this trail, as the paths are narrow and demanding throughout.

From the summit, visitors can see across the Kamikochi valley below and the entire Hotaka mountain range stretching across the horizon. The view is especially clear during early morning hours when light creates definition between valleys and peaks.